North America Native Plant

Hybrid Oak

Botanical name: Quercus ×howellii

USDA symbol: QUHO

Life cycle: perennial

Habit: shrub

Native status: Native to the lower 48 states  

Hybrid Oak: A Mysterious Native Worth Knowing About Meet the hybrid oak (Quercus ×howellii), one of California’s more enigmatic native trees that’s managed to fly under the radar of most gardening enthusiasts. This perennial oak species represents nature’s own botanical experiment—a naturally occurring hybrid that calls the Golden State home. ...

Hybrid Oak: A Mysterious Native Worth Knowing About

Meet the hybrid oak (Quercus ×howellii), one of California’s more enigmatic native trees that’s managed to fly under the radar of most gardening enthusiasts. This perennial oak species represents nature’s own botanical experiment—a naturally occurring hybrid that calls the Golden State home.

What Makes This Oak Special?

The hybrid oak is a multi-stemmed shrub that typically grows as a woody perennial, usually staying under 13-16 feet in height. Like most shrubs, it develops several stems from near ground level, though environmental conditions can sometimes coax it into different growth patterns. What makes this particular oak intriguing is its hybrid nature—it’s essentially nature’s own crossbreeding project, though the exact parent species aren’t well documented in readily available sources.

Where You’ll Find It Growing Wild

This native beauty is exclusive to California, making it a true Golden State original. Unfortunately, detailed information about its specific range within California is limited, which adds to its mysterious appeal.

The Challenge: Limited Information Available

Here’s where things get interesting (and a bit frustrating for us plant enthusiasts): Quercus ×howellii appears to be one of those plants that botanists know exists but haven’t extensively studied or documented. This means we’re missing key details about:

  • Specific growing conditions it prefers
  • USDA hardiness zones
  • Detailed care requirements
  • Wildlife and pollinator benefits
  • Wetland preferences
  • Rarity status

Should You Plant It?

The limited documentation surrounding this hybrid oak presents a bit of a dilemma. As a California native, it theoretically belongs in native plant gardens throughout its home state. However, the scarcity of cultivation information suggests it might be rare or simply not commonly grown.

If you’re determined to grow this particular oak, proceed with caution and responsibility:

  • Only source plants from reputable native plant nurseries
  • Never collect from wild populations
  • Contact local native plant societies or botanical gardens for guidance
  • Consider well-documented California native oaks as alternatives

Better-Known California Oak Alternatives

While you’re researching Quercus ×howellii, consider these well-documented California native oaks that offer proven garden performance:

  • Coast live oak (Quercus agrifolia)
  • Valley oak (Quercus lobata)
  • Blue oak (Quercus douglasii)
  • Interior live oak (Quercus wislizeni)

The Bottom Line

The hybrid oak represents one of those fascinating botanical mysteries that reminds us how much we still don’t know about our native plant communities. While its native status makes it theoretically desirable for California gardens, the lack of cultivation information means you’ll be venturing into uncharted territory if you choose to grow it.

For most gardeners, starting with better-documented California native oaks will provide more predictable results while still supporting local ecosystems. But for the truly adventurous gardener with connections to specialized native plant sources, Quercus ×howellii offers the chance to grow something genuinely unique—just remember to source responsibly and share your experiences with the broader native plant community!

Hybrid Oak

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Hamamelididae

Order

Fagales

Family

Fagaceae Dumort. - Beech family

Genus

Quercus L. - oak

Species

Quercus ×howellii Tucker [dumosa × garryana] - hybrid oak

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA